Moisture-impermeable package

ABSTRACT

A moisture-impermeable package including a flexible container having a bottom wall and side walls extending upwardly from the bottom wall. The side walls terminate in upper marginal ends which define an opening into the container. A thin, flexible, substantially non-stretchable closure is secured to the container and extends over the opening defined by the marginal ends. The closure has overlapping sections which define a slit that is elongate in a predetermined direction, and the container is in a differentially stressed condition to apply slit-sealing tension forces to the closure in the direction of slit elongation whereby the overlapping sections of the closure defining the slit are maintained in sealing relationship for establishing a substantially moisture-impermeable closure.

United States Patent [1 1 Spruyt et al.

[ MOISTURE-IMPERMEABLE PACKAGE [75] Inventors: Harry Spruyt, New York,N.Y.;

Louis S. Hoffman, Morristown, NJ.

[73] Assignee: Scott Paper Company, Philadelphia,

[22] Filed: Nov. 6, 1972 [21] Appl. No.: 303,703

[52] us. Cl. 221/63, 221/309 51 rm. (:1 B6511 1/00 58] Field ofSearch..22l/33-63,

[56] References Cited UNITED STATES PATENTS l/l956 Marcalus 221/483/1961 Harrison 220/24 R 10/1962 Deinert ISO/0.5 X 7/1965 McCarthy221/48 [451 Jan. 8, 1974 Primary Examiner-Robert B. Reeves AssistantExaminer-Thomas E. Kocovsky AttorneyMartin L. Faigus et al.

[ ABSTRACT A moisture-impermeable package including a flexible containerhaving a bottom wall and side walls extending upwardly from thebottomwall. The side walls terminate in upper marginal ends which define anopening into the container. A thin, flexible, substantiallynon-stretchable closure is secured to the container and extends over theopening defined by the marginal ends. The closure has overlappingsections which define a slit that is elongate in a predetermineddirection, and the container is in a differentially stressed conditionto apply slit-sealing tension forces to the closure in the direction ofslit elongation whereby the overlapping sections of the closure definingthe slit are maintained in sealing relationship for establishing asubstantially moisture-impermeable closure.

10 Claims, 4 Drawing Figures PATENTEU 8 4 SHEU 1 0F 2 PAIENIEUJAM 8I9T4SHEET 2 OF 2 MOISTURE-IMPERMEABLE PACKAGE BACKGROUND OF THE INVENTION 1.Field of the Invention This invention relates to a 1moisture-impermeable package, and more specifically to amoistureimpermeable package for retaining pre-moistened fibrous webstherein and for permitting easy removal of said fibrous webs therefrom.

' 2. Description of the Prior Art Pre-moistened wipers are extremelypopular for cleansing many portions of the human body. For example, suchwipers have provided the means for cleansing parts of the human bodyunder conditions where water, towels and the like are not available. Onespecific use for pre-moistened wipers is for cleansing excreta from thehuman anus, and usually after toilet paper has been used in the normalmanner. In such an application, the wiper normally is not a substitutefor toilet paper, but provides the final cleansing operation after thebulk of the excreta has been removed in the usual manner. Premoistenedwipers have many other applications. For example, they can be used tocleanse parts of the body other than the anus, such as under the arms,face, and- /or neck.

A wet wiper packaging system normally is prepared for dispensing byremoving an overwrap material, or other primary seal. After the primaryseal has been removed the packaging system still must be capable ofretaining the wet-wipers at an acceptable moisture level during theperiod of time required to use all of the wet-wipers, i.e., 30-6O days.

One wet wiper packaging system presently on the market is sold under thetrademark WET ONES by Lehn & Fink Products Division of Sterling Drug,Inc. The moisture-impermeable package of this system employs a containerhaving a main body member and a separate lid member. The lid member isprovided with cross-slits through which wet wipers can be removed, and acap forms a part of the lid member'for sealing the cross-slits. In theevent a user of the system fails to properly close the cap, the wetwipers may dry out prior to use. In addition, the packaging system issold with an aluminum foil sheet covering the open end of the main bodymember of the container. To use the system a mother must remove the lid,break the aluminum seal and feed a lead end of a continuous roll of wetwipers through the cross-slits. These preparatory operations aresomewhat cumbersome.

Other moisture-impermeable packages have been designed for products suchas pills, tablets and the like. These packages normally include a mainbody portion and a lid pivotally secured thereto. The lid is pivotalbetween an open position for permitting the removal of pills and/ortablets, and a closed position to seal the package. In the event the lidis not properly closed, moisture can seep into the package to therebyadversely affect the product contained therein.

US. Pat. No. 3,401,498 issued to Garvin, discloses and claims a methodfor capping or closing a container suitable for use in vending machines.According to the Garvin method an unsupported end portion of thecontainer is placed under heat and pressure to uniformly deform it inall directions as a plastic cover material is secured over one endthereof. After the cover is secured to the container the pressure on thecontainer is removed to permit the container to spring outwardly andapply tension to the cover uniformly in all directions. Thisconstruction, while providing a moistureimpermeable packaging system, isnot associated with a packagehaving a slit therein for permitting theremoval of contents from within the package while maintaining thepackage in a moisture-impermeable condition during non-use.

US. Pat. No. 2,975,931, issued to Harrison, relates to a containerprovided with a Mylar covering material thereover. The container has atapered skirt portion with a maximum width in the midsection thereof,and this maximum width section applies tension to the covering material.The covering material is not provided with a slit therein to permit theremoval of contents SUMMARY OF THE INVENTION A moisture-impermeablepackage includes a flexible container having a bottom wall and sidewalls extending upwardly from said bottom wall, said side wallsterminating in upper marginal ends defining an opening into-thecontainer. A thin, flexible, substantially nonstretchable closure issecured to the container over the opening thereof, and the closure hasoverlapping sections which define a slit that is elongate in apredetermined direction. The container is differentially stressed forapplying slit-sealing tension forces to the closure in the direction ofslit elongation to maintain the overlapping sections of the closure insealing relationship for establishing a moisture-impermeable package.

I In the preferred embodiment of this invention the container is moldedin a configuration such that the upper marginal ends define aquadrilateral (preferably a parallelogram) in plan view. Theparallelogram preferably is in the form of a rhomboid having a longdiagonal dimension and a short diagonal dimension. The container istwisted into a differentially stressed condition in which the uppermarginal ends define a rhomboid which is canted in the oppositedirection from its initially formed direction, as a result of which thelong diagonal dimension is foreshortened. The closure is adhered, withsome slack therein, to the twisted container with the direction of slitelongation along the foreshortened diagonal dimension of the container.The twisting force applied to the container is then removed, and thesomewhat slack condition of the closure permits the container to moveslightly in a direction opposite to its twisted direction to assume anequilibrium position in which the foreshortened diagonal dimension islengthened and the upper marginal ends of the container define asubstantially rectangular configuration in plan view. In this manner,potential energy is stored in the twisted container to impart theslit-sealing tension forces to the closure in the direction of slitelongation.

The seal which is established in the package of this invention iseffective to maintain the wet wipers at a functional moisture level forthe period of time required to utilize all of wipers, i.e., 30-60 days.The

package does not have a separate pivotal lid member.

which, as a result of improper closure thereof, can result in moistureescaping from the web to render the product unacceptable prior to usethereof.

A wet wiper most easily is removed from the package of this invention byplacing the thumb and forefinger through the slit in the closure toengage the uppermost wet wiper within the container. The container issufficiently flexible to flex to accommodate the opening of the slitresulting from fingers being inserted therethrough. After the fingersand engaged product are removed from the confines of the slit, thecontainer returns to its equilibrium position to cause the overlap pingsections of the closure to engage each other and provide amoisture-impermeable seal. The nonstretchable nature of the closurefurther assures that an impermeable seal will be maintained afterrepeated insertion of the fingers into the package. Preferably, theclosure is transparent to permit the user to view into the package whileremoving a wet wiper. Other objects and advantages of this invention,including a better understanding thereof, can be had by referring to thedetailed description which follows, taken in conjunction with thedrawings, in which:

, BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of amoisture-impervious package according to this invention with partsbroken away to show wet wipers packaged therein;

FIG. 2 is a side elevation view of the container employed in thisinvention in its originally molded configuration without the closureadhered thereto;

FIG. 3 is an end elevation view of the container employedin thisinvention in its originally molded configuration without the closureadhered thereto; and

FIG. 4 is a plan view of the container employed in this inventionwherein the configuration of the container in its originally moldedconfiguration is shown in solid lines, and the outer boundaries of thecontainer as the closure-is adhered thereto, and in its equilibriumposition are shown in phantom lines.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION rounded edgesand upper marginal ends are substantially parallel. The opposed longside walls 24 and 26 are canted in opposite directions relative to ahorizontal plane 56 in the initially molded configuration ofthecontainer 10 (FIG. 2). In addition, these long side walls are canted inopposite directions relative to vertical planes 58 and 60 (FIG. 3). Inthis manner, the opposed long side walls 24 and 26 are substantiallyinverted mirror images of each other.

The same canted relationship exists between the opposed short side walls28 and 30. More specifically, the short side walls 28 and 30 are cantedin opposite directions relative to the horizontal plane 56 (FIG. 3), andare canted in opposite directions relative to vertical planes 62 and 64(FIG. 2).

As a result of the canted relationship of the side walls, the bottomwall 22 is nonplanar and is disposed in canted relationship with respectto horizontal plane 56.

The upper marginal ends 40, 42, 48 and 50, in the form of flangesextending outwardly from the side walls, define an opening into thecontainer 12. Preferably the outer end of the flanges extend downwardlyto enhance the rigidity of the upper end of the container. As a resultof the above described construction of the container, in its initiallymolded configuration, the upper marginal ends define a rhomboid in planview having a long diagonal dimension D, and a short diagonal dimensionD, (FIG. 4).

To form the package 10 elastically deforming twisting forces, asindicated by arrows 66 and 68 (FIG. 3),

are applied to the flexible container 12 to reorient the I Referring toFIG. 1, a moisture-impermeable pack- 7 age 10 according to thisinvention includes a flexible container 12 and a thin, flexible,non-stretchable closure -14 secured to the container over an open endthereof. The closure 14 is formed of overlapping nonstretchable plasticsheets 16 and I8, and the overlapping sections of these sheets define aslit 20 extending in a predetermined direction. In the preferredembodiment of this invention the slit 20 extends along diagonal D Thecontainer 12 includes a bottom wall 22, opposed long side walls 24 and26, and opposed short side walls 28 and 30. The long and short sidewalls extend upwardly and diverge outwardly from the bottom wall 22.

' The long side walls 24 and 26 are joined to the bottom wall throughlower rounded edges 32 and 34 (FIG. 2), respectively. The short sidewalls 28 and 30 are joined to the bottom wall through lower roundededges 36 and upper marginal ends into a rhomboid which is canted in theopposite direction from its initially deformed disposition, as indicatedat 46 in broken line representation in FIG. 4. The twisting of thecontainer can be accomplished by inserting it into a mold cavity havingthe appropriate configuration. By twisting the container as indicatedabove, the long diagonal dimension D, is foreshortened to a newdimension D, and the short diagonal dimension D, is lengthened to a newdimension D, (FIG. 4). With the container maintained in its reorientedcondition, the plastic sheets 16 and 18 are adhered to the marginal ends40, 42, 48 and 50 by any suitable means. For example, an adhesive whichis compatible with both the container and the plastic sheet can beutilized, or a hot pressure bonding technique can be utilized. Thespecific means of attaching the plastic sheets to the container is notmitirn, ttbenr ssm invention- The sheets 16 and 18 are adhered to thecontainer in a slack condition while the container is maintained in itsdeformed condition, and the overlapping sections of the sheet define theelongate slit 20 which is disposed lqns.tligf tesh rtc d a n dimensionD!" of the container. After the plastic sheets 16 and 18 are ad hered tothe container 12, the deforming forces are removed from the container,and the container will move toward its initially formed condition whichcauses the diagonal dimension D1 to lengthen. The container 12lengthening of the diagonal dimension D In the t: ut

condition of the plastic sheets 16 and 18 the package 10 assumes anequilibrium condition in which the upper marginal ends of the container12 define a substantially rectangular configuration in plan view, asindicated at 54 in dot-dash representation (FIG. 4). In this equilibriumcondition, the diagonal dimension along the slit direction is indicatedas D, (FIG. 4) and is greater than D1 but less than D,. Potential energy is stored in the pla stic container in the equilibrium condition,as a result of its elastic memory for its originally formed condition.This potential energy is responsible for applying continuous tensionforces to the plastic sheets in the direction of slit elongation tomaintain the overlapping sections of the plastic sheets in sealingrelationship with respect to each other. If desired any suitableadhesive or self-stick material can be included on one or both of theplastic sheets in the overlapping section (5) to assure that aneffective seal is established between the overlapping sections.

In the preferred embodiment of this invention, the moisture impermeablepackage is utilized to retain a plurality of premoistened fibrous webs70 therein, such as the pre-moistened wipers disclosed in US. Pat.application Ser. Nos. 263,145, filed June 15, 1972; and 237,859, filedMar. 14, 1972, both of which are assigned to Scott Paper Company (FIG.1). These webs 70 can be folded in any conventional manner and stackedupon each other. Preferably, the webs are folded to provide grippingedges 72 on the side of each web closest to the flexible closure 14. Apre-moistened wiper is removed most easily by inserting the thumb andforefinger through the slit defined by the overlapping sections of theplastic sheets 16 and 18 to thereby grip an edge 72 of the uppermostwiper 70.

The container is sufficiently flexible to reorient itself to accommodatethe opening of the slit by the fingers. After a wiper has been removed,the package will return to its equilibrium condition to causeoverlapping sections of the plastic sheet 16 and 18 to engage each otherand form a moisture-impermeable seal. The establishment of themoisture-impermeable seal after repeated insertion of the fingers intothe container is further assured by the fact that the plastic sheets aresubstantially non-stretchable.

The container 12 preferably is constructed of a plastic material whichis flexible and self-supporting. Exemplary materials which can be usedto form the container 12 are polypropylene and polyvinyl chloride, aswell as laminated constructions of these and other plastic materials.Othe r flexible materials can be utilized provided they are compatiblewith the items contained within the container 12, and are sufficientlyself-sustaining. Preferably, the container is made in a thermo-formingoperation from 30 mil thick plastic sheet material.

The flexible closure preferably is constructed of thin plastic laminatessuch as mylar laminated to polyethylene. The mylar is tough andnon-stretching, to thereby impart the non-stretchable characteristics tothe closure. The polyethylene has excellent heat sealing prop erties,and is disposed adjacent the surface of the container when a heatsealing operation is utilized to secure the film to the container. Othermaterials can be utilized for the closure, provided that such materialscan be utilized to form a closure which is substantiallynon-stretchable, and which can be adhered to the container 12 by themeans desired.

Although one specific pre-shaped configuration of a container 12 hasbeen described, other pre-shaped configurations can be utilized,depending upon the shape of the items to be packaged within thecontainer. The

important criteria is that the container be preshaped such that uponapplying elastically deforming forces thereto; the container isdifferentially stressed into a condition such that slit-sealing tensionforces are applied to the closure after removal of the elasticallydeforming forces. For example, the container can be formed into aconfiguration wherein the upper marginal ends define an ellipse having along major axis, and a shorter minor axis. ln such an arrangement, theelastically deforming forces would be applied to cause the container toassume a new configuration in which the upper marginal ends define anellipse with its major and minor axes disposed to the respective majorand minor axes in the originally formed container. The non-stretchableplastic material would be adhered to the container with the slitoriented in the direction of the foreshortened major axis, i.e., theminor axis in the elastically deformed container. When the elasticallydeforming forces are removed, the container will tend to move toward itsoriginally formed condition, to thereby cause a lengthening of theforeshortened direction to create a taut condition in the closure toeffect the moisture-impermeable seal.

What is claimed is:

1. A moisture-impermeable package comprising:

A. a flexible container having a bottom wall and side walls, said sidewalls extending upwardly from said bottom wall and terminating in uppermarginal ends which define an opening into the container;

B. a thin, flexible, substantially non-stretchable closure secured tosaid container and extending over the opening thereinto, said closurehaving overlapping sections defining a slit which is elongate in apredetermined direction; and

C. said container being in an equilibrium, differentially stressedcondition for applying slit-sealing tension forces to said closure inthe direction of slit elongation, whereby the overlapping sections ofsaid closure defining the slit are maintained in sealing relationshipwith respect to each other to establish a substantiallymoisture-impermeable closure for the container.

2. The package according to claim 1, including moistened fibrous webswithin said container.

3. The package according to claim 1, wherein the upper marginal ends ofsaid side walls define a quadrilateral in plan view, said slit beingoriented in a diagonal direction of said quadrilateral.

4. The package according to claim 3, wherein said quadrilateral issubstantially rectangular in plan view.

5. The package according to claim 1, wherein said container ispre-shaped in a configuration different from the equilibriumconfiguration which is established with the closure adhered thereto.

6. The package according to claim 5, wherein the upper marginal ends ofsaid side walls define a quadrilateral in plan view, said slit beingoriented in a diagonal direction of said quadrilateral.

7. The package according to claim 6, wherein the upper marginal ends ofthe side walls of the pre-shaped container generally define a rhomboidin plan view, said upper ends being disposed in a substantiallyrectangular configuration in plan view when the container is in anequilibrium condition with the closure secured thereto.

8. A moisture-impermeable package comprising:

said closure having overlapping sections defining a slit which iselongate along the shortened diagonal dimension of the stressedcontainer.

9. The package according to claim 8, wherein the quadrilateral definedby the upper marginal ends of the stressed container is substantiallyrectangular.

10. The package according to claim 9, wherein said side walls includeopposed substantially parallel long side walls and opposed substantiallyparallel short side walls.

1. A moisture-impermeable package comprising: A. a flexible containerhaving a bottom wall and side walls, said side walls extending upwardlyfrom said bottom wall and terminating in upper marginal ends whichdefine an opening into the container; B. a thin, flexible, substantiallynon-stretchable closure secured to said container and extending over theopening thereinto, said closure having overlapping sections defining aslit which is elongate in a predetermined direction; and C. saidcontainer being in an equilibrium, differentially stressed condition forapplying slit-sealing tension forces to said closure in the direction ofslit elongation, whereby the overlapping sections of said closuredefining the slit are maintained in sealing relationship with respect toeach other to establish a substantially moisture-impermeable closure forthe container.
 2. The package according to claim 1, including moistenedfibrous webs within said container.
 3. The package according to claim 1,wherein the upper marginal ends of said side walls define aquadrilateral in plan view, said slit being oriented in a diagonaldirection of said quadrilateral.
 4. The package according to claim 3,wherein said quadrilateral is substantially rectangular in plan view. 5.The package according to claim 1, wherein said container is pre-shapedin a configuration different from the equilibrium configuration which isestablished with the closure adhered thereto.
 6. The package accordingto claim 5, wherein the upper marginal ends of said side walls define aquadrilateral in plan view, said slit being oriented in a diagonaldirection of said quadrilateral.
 7. The package according to claim 6,wherein the upper marginal ends of the side walls of the pre-shapedcontainer generally define a rhomboid in plan view, said upper endsbeing disposed in a substantially rectangular configuration in plan viewwhen the container is in an equilibrium condition with the closuresecured thereto.
 8. A moisture-impermeable package comprising: A. aflexible container having a bottom wall and side walls extendingupwardly from said bottom wall and terminating in upper marginal endswhich define a quadrilateral in plan view, said container being in anequilibrium, stressed condition in which one diagonal dimension of thequadrilateral is shorter, and the other diagonal dimension is longerthan the corresponding diagonal dimensions of the unstressed container;and B. a thin, flexible closure secured to said container and extendingover the opening into said container, said closure having overlappingsections defining a slit which is elongate along the shortened diagonaldimension of the stressed container.
 9. The package according to claim8, wherein the quadrilateral defined by the upper marginal ends of thestressed container is substantially rectangular.
 10. The packageaccording to claim 9, wherein said side walls include opposedsubstantially parallel long side walls and opposed substantiallyparallel short side walls.